如何在vb.net中进行动态sql查询？

Question

i'm trying to do this dynamic sql query in vb.net where i declare two variable and pass a SELECT on each variable

 Dim cmd As New SqlCommand("Declare @val1 int " & _
                           "Declare @val2 int " & _
                           "SET @val1 = 'SELECT Count(*) from table1tbl'" & _
                           "SET @val2 = 'SELECT Count(*) from table2tbl'", conn)
    Dim rdr As SqlDataReader = cmd.ExecuteReader
    rdr.Read()
    Dim str1 = rdr("@val1")
    Dim str2 = rdr("@val2")
    rdr.Close()

i know this code is not right..so how to makes this right ? tnx in advance

Answer 1

You can't do that from a sqlcommand, so to execute your code you'd have to create a stored procedure and add to the end:

Select @val1, @val2

To return the values as a table that you are creating.

I assume that you are doing something more creative than your actual example, but is there anyway of including everything in your select statement? A correct version should go something like this:

Select (select count(*) from table1tbl), (select count(*) from table2tbl)

That will return the data in the format you want so that you can read it with the code you have posted.

Answer 2

Dim sQuery as String
Dim val1 
Squery = <a> SELECT Count(*) from table1tbl </a>.Value
Using cmd As New SqlCommand(sQuery, con)
  If cmd.Connection.State <> ConnectionState.Open Then
    cmd.Connection.Open()
  End If
val1 = cmd.ExecuteScalar()
End Using